Yield and Economic Aspects of Irrigated Cropping Systems in Eastern Nebraska
1991
Peterson, W. R. | Walters, D. T. | Supalla, R. J. | Olson, R. A.
Current economic conditions in agriculture and concerns over ground-water pollution have led to efforts to find more efficient methods of crop production. A field experiment was initiated in 1982 on a Sharpsburg silty clay loam in eastern Nebraska to examine the effects of manure and increasing levels of N, P, K, and micronutrients on grain yield, return over variable costs (ROVC), and variability of ROVC of an irrigated corn (Zea mays L.)-soybean [Glycine max (L.) Merr.]-wheat (Triticum aestivum L.) rotation (CSW) and irrigated continuous corn (CC). Manure was a good fertilizer substitute for producers who have access to it. Corn yields at optimum N-rate were 20% greater for rotation corn (RC) than for CC. Optimum economic yields were produced at very moderate levels of applied commercial fertilizer and yield stability was not improved with high fertilizer inputs. The ROVC for CSW was lower than that for CC but was less variable from year to year, indicating a measure of income stability could be attained at the expense of a reduction in ROVC. If wheat were omitted from the rotation, a corn-soybean (CS) rotation would have average ROVC slightly above that for CC, but variability also would increase to a level comparable with CC. Continuous corn production can be profitable through good fertilizer and irrigation management, but the level of management necessary is greater than that needed when crops are rotated.
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